Magnetotransport properties of interconnected magnetic nanowires and multilayers

This Master's thesis investigates the magnetic and magnetotransport properties of novel three-dimensional interconnected multilayered nanowire networks of NiCoCu/Cu. Very high giant magnetoresistance (GMR) of 40% at room temperature and 80% at 20 K, has been measured, in the current-perpendicular-to-plane (CPP) geometry. Track-etched polycarbonate membranes with interconnected pore network, were used for "bottom-up" template-assisted electrodeposition of samples from single electrolyte baths. The synthesis parameters have been systematically optimised in order to yield samples with high CPP-GMR. Extensive investigations of changing parameters, such as the Cu^(2+) electrolyte concentration, and nanowire packing density, have been carried out. Results show that electrodeposited interconnected multilayered nanowire networks of NiCoCu/Cu are good candidates for studying CPP-GMR properties. The GMR effect seems to be somewhat affected by the Cu^(2+) electrolyte concentration, and significantly enhanced upon reduction of the nanowire packing density. The reduced amount of crossing zones in the nanowire network might be the cause of this enhancement. However, the samples with low nanowire packing density suffers from mechanical instability, which creates several experimental challenges and poor reproducibility. If these challenges become sorted out, these interconnected multilayered nanowire networks with low packing density will emerge as excellent candidates for CPP-GMR research.Master [120] : ingénieur civil en chimie et science des matériaux, Université catholique de Louvain, 201